1. Field of the Invention
This invention is in the field of hybrid optical fiber and CATV cable communications systems and methods.
2. Description of the Related Art
Cable television (CATV), originally introduced in the late 1940's as a way to transmit television signals by coaxial cables to houses in areas of poor reception, has over the years been modified and extended to enable the cable medium to transport a growing number of different types of digital data, including both digital television and broadband Internet data.
Over the years, this 1940's and 1950's era system has been extended to provide more and more functionality. In recent years, the CATV system has been extended by the use of optical fibers to handle much of the load of transmitting data from the many different CATV cables handling local neighborhoods, and the cable head or operator of the system. Here the data will often be transmitted for long distances using optical fiber, and the optical (usually infrared light) signals then transformed to the radiofrequency (RF) signals used to communicate over CATV cable (usually in the 5 MHz to 1-GHz frequencies) by many local optical fiber nodes. Such systems are often referred to as hybrid fiber cable systems, or HFC systems. The complex electronics that are used by the cable operator to inject signals (e.g. data) into the system, as well as extract signals (e.g. data) from the system are often referred to as Cable Modem Termination Systems or CMTS systems.
A more detailed discussion of prior art in this field can be found in U.S. Pat. No. 8,311,412, the contents of which are incorporated herein by reference.
Prior art work with various types of CMTS systems and fiber nodes includes Liva et. al., U.S. Pat. No. 7,149,223; Sucharczuk et. al. US patent application 2007/0189770; Sawyer et. al., US patent application 2003/0066087; and Amit, U.S. Pat. No. 7,197,045.
U.S. patent application Ser. No. 12/692,582, now (U.S. Pat. No. 8,311,412) taught the advantages of producing a new type of optical fiber node, there called a Cable Modem Remote Termination System (CMRTS) device, which essentially pushed much of the functionality (such as generating QAM signals) of the prior art Cable Modem Termination Systems (CMTS) from the central cable head down to many distributed optical fiber nodes servicing neighborhood CATV cables
Motorola, in February 2012, proposed a non-virtual “Converged Cable Access Platform” (CCAP). This is exemplified in their February 2012 publication CCAP 101: Guide to Understanding the Converged Cable Access Platform. As they discussed, “With consumers demanding more content on more screens, cable operators are seeking a cost-effective strategy for migrating from conventional MPEG-based video delivery to IP video transport. The Converged Cable Access Platform (CCAP) was designed with this goal in mind, and proposes to combine data and video delivery as a first step on the migration path. While cable operators today implement data and video QAMs on separately managed and controlled platforms, CCAP provides a blueprint for combining CMTS and edge QAM functionality in one hardware solution. CCAP promises significant improvements in QAM channel density, and the flexibility for cable operators to expand data and video services while also planning for a future world of all-IP delivery.”
Other recent work on Converged Cable Access Platforms includes the Cable labs Specification for Data-Over-Cable Service Interface Specifications Converged Cable Access Platform Converged Cable Access Platform Architecture Technical Report CM-TR-CCAP-V03-120511, released May 11, 2012.
Juniper Networks MX 3D Universal Edge routers were described in Juniper Networks datasheet 1000208-006-EN April 2010, “MX Series 3D Universal Edge Routers”.